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    <!-- 使用for循环 - 求出数组元素的和 [5, 8, 9, 2, 1, 5] -->
     <script>
        let arr =[5, 8, 9, 2, 1, 5]
        let a=0
        for (let index = 0; index < arr.length; index++) {
            const element = arr[index];
           
            a+=element
            
        }
        console.log(a);
        
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